The present disclosure relates to subject matter contained in priority Japanese Patent Application No. 2000-5140773, filed on May 12, 2000, the contents of which is herein expressly incorporated by reference in its entirety.
1. Technical Field of the Invention
The present invention relates to a laser drilling machine having a dust collector and a method for collecting dust in the laser drilling machine.
2. Description of Related Art
Laser drilling machine is used for forming a minute hole having a diameter of about 100 xcexcm to several 10 xcexcm in a workpiece by burning off a portion of the workpiece with a laser beam. The drilling process produces smoke and dust and the minute particles of dust are scattered around, deteriorating the working environment. Dust adhered to the lens of the laser emitter induces chemical reaction with the lens and decreases working efficiency.
Dust produced during the drilling, therefore, must be removed immediately. A conventional technique commonly known as xe2x80x9cpush-pull methodxe2x80x9d involves supplying air into a space between the lens and the workpiece from one side and exhausting air from the other side of the space, thereby collecting the minute particles of dust.
The dust-collecting performance by this push-pull method is variable depending on the positions of the air inlet and outlet and the air supply/exhaust capacity. Particularly when the design of the laser drilling machine does not permit a closed space to be formed between the lens and the workpiece because of the allowance for free relative movements of the lens and the workpiece, sufficient dust collecting performance cannot be expected simply by supplying and exhausting air in view of the clearance in the space. As a result, dust is inevitably deposited on the workpiece or on the lens, contaminating or altering the characteristics of same.
The present invention has been devised in light of the above-described problem encountered by the prior art, and it is an object of the invention to provide a dust collector for a laser drilling machine which enables efficient discharge of dust by a draft of air flowing from an air inlet toward an outlet.
To achieve the object, the present invention provides a dust collector used in a laser drilling machine arranged between a lens table and a workpiece to be processed. The dust collector includes four side walls for defining therein a space, an upper inlet port and a lower inlet port for introducing air into the space provided in one of the four side walls, the lower inlet port being capable of supplying air in an amount 1.5 to 4.5 times more than that supplied by the upper inlet port, and an exhaust port for exhausting air from the space provided in one of the four side walls opposite the upper inlet port and the lower inlet port, wherein the upper inlet port and the lower inlet port altogether have an air supply capacity which is 30 to 70% of the amount of air exhausted from the exhaust port.
A plurality of flow adjusting grooves are formed on lower faces of a pair of side walls located on both sides of a draft of air flowing from the upper inlet port and the lower inlet port toward the exhaust port. The flow adjusting grooves should preferably be inclined inwards to the draft of air at an angle of 20xc2x0 to 50xc2x0.
The dust collector further includes a closure member for closing a gap formed between the lower surface of the side wall in which the exhaust port is provided, the closure member having its distal end being positioned within the space and a surface inclined upwards toward the exhaust port. The dust collector further includes an upper side wall above the space around the lens table such as to face an outer wall of the lens table with a gap of 1 mm or less over a vertical length of 15 mm or more.
These and other objects and characteristics of the present invention will become further clear from the following description with reference to the accompanying drawings.